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| Cutaneous myoepithelioma—classical variant | Cutaneous myoepithelioma—syncytial variant |
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| Growth pattern | Trabecular, reticular, plexiform (rare) | In sheets, solid, and syncytial |
| Cytology | Mixed: epithelioid, fusiform, clear, or plasmocytoid cells | Ovoid, fusiform, or histiocytoid |
| Stroma | Chondromyxoid, myxoid, or hyaline | Sparse; presence of adipose metaplasia seems to be more frequent than in the classical variant |
| Immunohistochemistry |
| Calponin | (+) 86%–100% | (+) >85% |
| SMA | (+) in up to 60% of cases | (+) 70% |
| Desmin | (-) 80%–100% | (-) 80%–100% |
| EMA | (+) 42% | (+) 100% |
| Cytokeratins (pankeratin, AE1/AE3, Cam5.2) | Diffuse and intense positivity in most cases (93%–100%) | Focal positivity in a few cases (12%) |
| S-100 | (+) 72%–100% | (+) 86%–100% |
| GFAP | (+) variable, 27%–54% | (+) 42% |
| p63 | (+) variable, 7%–45% | (+) 54% |
| Molecular alteration | EWSR1 gene rearrangement. Identified fusion genes include PBX1, PBX3, POU5F1, ZNF444, DUX4, ATF1, NR4A3, CREB1. | EWSR1 gene rearrangement. The fusion genes are different from the classical variant. |
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